1. Field of the Invention
The present invention relates to multiple countershaft, change gear transmissions that include a main shaft, and in particular to multiple countershaft, change gear transmissions having a device for supporting the main shaft on-center when the transmission is in neutral.
2. Description of the Related Art
Change gear transmissions, that is, transmissions utilizing either simple or compound main shafts in connection with multiple countershafts, wherein the main shaft, the main shaft gears and/or the countershaft gears are mounted in a radially floating manner relative to the other gears, are well known in the prior art. Examples of such transmissions may be seen by reference to U.S. Pat. Nos. 3,105,395; 3,255,644; 3,283,613; 3,335,616; 3,349,635; 3,378,214; 3,500,695; and 3,648,546, all of which are hereby incorporated by reference. Transmissions of this type commonly include axially slidable clutches that are splined for rotation with the main shaft. These clutches are moved by a shifting mechanism, such as a rail or lever type shifting mechanism, to engage the main shaft for rotation with the main shaft gears.
An undesirable limitation of transmissions that include a radially floating main shaft is that the main shaft tends to fall off-center when the transmission is shifted to neutral and no torque is being transmitted through to the main shaft. Once off-center, greater effort is required by the shifting mechanism to move the axially slidable clutches and shift the transmission into gear.